The Minoan eruption was a very powerful volcanic eruption that caused a lot of destruction on the Aegean island of Thera (also called Santorini) around 1600 BC. It damaged the Minoan settlement at Akrotiri and harmed communities and farmland on nearby islands and the coast of Crete, which were affected by later earthquakes and tsunamis. With a Volcanic Explosivity Index (VEI) of 7, the eruption released about 28–41 km (6.7–9.8 mi) of dense-rock equivalent (DRE), making it one of the largest volcanic events in human history. Because volcanic ash from the Minoan eruption is found in many archaeological sites across the Eastern Mediterranean, knowing its exact date is very important. Scientists have debated this date for many years, but no clear answer has been reached.
There are no clear ancient records describing the eruption, but some believe the volcanic plume and lightning might have been mentioned in the Egyptian Tempest Stele. However, recent studies using carbon dating on items from the early 18th Dynasty have questioned this connection. The Chinese Bamboo Annals recorded unusual yellow skies and summer frost at the start of the Shang dynasty, which may have been caused by a volcanic winter, similar to the cold weather that followed the 1815 eruption of Mount Tambora, known as the Year Without a Summer.
Eruption
Geological evidence shows that the Thera volcano erupted many times over hundreds of thousands of years before the Minoan eruption. This process repeated, with the volcano erupting violently and then collapsing into a circular seawater-filled caldera, forming small islands around it. The caldera would slowly refill with magma, building a new volcano, which erupted and then collapsed in an ongoing cyclical process.
Immediately before the Minoan eruption, the caldera walls formed a nearly continuous ring of islands, with the only entrance between Thera and the small island of Aspronisi. This powerful eruption occurred on a small island just north of the existing island of Nea Kameni in the center of the caldera. The northern part of the caldera was filled with volcanic ash and lava, then collapsed again.
Estimating the size of the eruption, especially the underwater pyroclastic flows, has been difficult because most of the erupted material was deposited in the sea. These challenges make it hard to determine the exact volume of the Minoan eruption, with estimates ranging from 13 to 86 cubic kilometers (3.1 to 20.6 cubic miles) DRE.
Recent studies of marine sediments and seismic data collected from 2015 to 2019 suggest the eruption expelled between 28 and 41 cubic kilometers (6.7 to 9.8 cubic miles) DRE of material.
The study found that the initial major eruption phase, called the Plinian phase, released 14 to 21 cubic kilometers (3.4 to 5.0 cubic miles) of magma, making up half of all erupted materials. This was followed by smaller phases: 3 to 4 cubic kilometers (0.72 to 0.96 cubic miles) of co-ignimbrite ash, 5 to 9 cubic kilometers (1.2 to 2.2 cubic miles) of pyroclastic flows, and 5 to 7 cubic kilometers (1.2 to 1.7 cubic miles) of deposits within the caldera.
This eruption is similar in size to other major eruptions in the last 2,000 years, including the 1815 eruption of Mount Tambora, the 1257 Samalas eruption, the Hatepe eruption of Lake Taupo around AD 230, and the 946 eruption of Paektu Mountain.
On Santorini, a 60-meter-thick layer of white tephra covers the soil, clearly showing the ground level before the eruption. This layer has three distinct bands that mark different eruption phases. Studies identified four major eruption phases and one minor tephra fall before the main event. The thinness of the first ash layer and the lack of erosion from winter rains suggest the volcano gave the local population a few months’ warning. No human remains have been found at the Akrotiri site, indicating the population may have fled due to earlier volcanic activity. Evidence also suggests Santorini experienced one or more earthquakes months before the eruption, damaging local settlements.
The first major eruption phase (BO 1 /Minoan A) produced up to 7 meters of pumice and ash, with some rock fragments, southeast and east of the caldera. Archaeological evidence shows that man-made structures were buried with little damage. The second (BO 2 /Minoan B) and third (BO 3 /Minoan C) phases involved pyroclastic surges, lava fountains, and possibly tsunamis. Structures not buried during Minoan A were completely destroyed. The third phase also began the collapse of the caldera. The final major phase (BO 4 /Minoan D) included varied activity: rock-rich base surge deposits, lava flows, lahars, and co-ignimbrite ash-fall deposits. This phase completed the caldera collapse, leading to massive tsunamis.
Geomorphology
Although the exact fracturing process is not yet known, elevation-based analysis shows the caldera formed just before the eruption. The island was smaller, and the southern and eastern coastlines had moved inland. During the eruption, the landscape was covered with pumice sediments. In some areas, the coastline was covered by thick layers of tuff. In other places, the coastlines stretched further into the sea. After the eruption, the island's shape was changed by a strong erosion period, during which pumice was gradually moved from higher areas to lower ones.
Volcanology
The eruption was of the Plinian type and involved rhyodacite. It created an eruption column estimated to be 30 to 35 kilometers (19 to 22 miles) high, reaching the stratosphere. The magma beneath the volcano came into contact with a shallow marine embayment, causing powerful phreatomagmatic explosions.
The eruption also produced tsunamis up to 35 to 150 meters (115 to 492 feet) high, which caused major damage to the northern coastline of Crete, 110 kilometers (68 miles) away. Coastal towns like Amnisos were affected, with building walls knocked out of alignment. On the island of Anafi, 27 kilometers (17 miles) to the east, ash layers 3 meters (10 feet) deep were found, as well as pumice layers on slopes 250 meters (820 feet) above sea level.
Pumice deposits found elsewhere in the Mediterranean may have been carried by the Thera eruption. Ash layers discovered in cores taken from the seabed and lakes in Turkey show that the heaviest ashfall occurred to the east and northeast of Santorini. The ash found on Crete was from an earlier phase of the eruption, weeks or months before the main eruptive events, and had little effect on the island. Ash deposits from Santorini were once thought to be found in the Nile Delta, but this has since been proven incorrect.
Eruption dating
The Minoan eruption is a key event used to help date the Bronze Age in the Eastern Mediterranean. It gives a clear reference point for organizing the timeline of the second millennium BC in the Aegean region, as evidence of the eruption has been found across the area. However, dates from archaeology, which rely on studying artifact styles and Egypt’s timeline, are about 100 years younger than the radiocarbon dates for the Minoan eruption. This difference has caused scientists to debate whether the timelines of the Aegean and Egypt are not properly aligned.
Archaeologists created the Late Bronze Age timelines for cultures in the Eastern Mediterranean by studying the styles of artifacts found in different layers of ancient sites. If the types of artifacts can be matched correctly, the order of the layers can be determined. This method is called sequence dating or seriation. In Aegean timelines, the frequent exchange of objects and styles allows archaeologists to compare the relative timeline of the Aegean with Egypt’s absolute timeline, helping to assign exact dates to Aegean events.
The Minoan eruption has been clearly placed in the late or end of the Late Minoan IA (LM-IA) period on Crete and the late or end of the Late Helladic I (LH-I) period on the mainland. The debate centers on which Egyptian time period was happening at the same time as LM-IA and LM-IB. Archaeological work on Crete over the past century has linked the late LM-IA period to Dynasty XVI in Egypt and the start of Thutmose III’s reign. Stone vessels found in LH-I shaft graves match styles from Egypt’s New Kingdom. Pumice workshops on Santorini and a milk bowl found there before the eruption also show New Kingdom designs. An Egyptian inscription on the Ahmose Tempest Stele describes a disaster similar to the Minoan eruption. Together, these clues suggest the eruption occurred after Ahmose I became king. Based on traditional Egyptian and radiocarbon timelines, Ahmose I likely became king around 1550 BC or between 1570–1544 BC (IntCal04) or 1569–1548 BC (IntCal20). Archaeological evidence points to the eruption happening between about 1550 and 1480 BC.
Some scientists argue that the connection between Aegean and Egyptian pottery styles allows for some flexibility in dating. Other interpretations of LM-IA and LM-IB pottery styles differ from the traditional view and could support an earlier start for these periods. Pottery comparisons were less certain before the LM-IIIAI/Amenhotep III period. Some researchers say pumice workshops and the Ahmose Tempest Stele only show the earliest possible date for the eruption. The timing of pottery with Santorini milk bowl styles in other areas is unclear and might predate the eruption. Information about stone vessel styles during this time is also missing.
Radiocarbon dating can be inaccurate because the amount of carbon in the atmosphere changed over time. Scientists adjust raw radiocarbon dates using calibration curves, which are updated regularly. The accuracy of these dates depends on how well the calibration curve matches the actual carbon levels for the time period. The most recent calibration curve, IntCal20, was introduced in 2020. Early radiocarbon dates from the 1970s showed large differences and were initially dismissed. Over time, better calibration, analysis, and methods narrowed the possible eruption dates. Radiocarbon evidence now strongly supports an eruption in the late 17th century BC.
In 2018, scientists found that previous calibration curves (IntCal) might have been slightly off between 1660–1540 BC. This discovery, confirmed by other labs, led to the updated IntCal20 curve. However, some studies later questioned whether tree ring dating of an olive branch used for wiggle-matching could be off by decades. In 2020, research on juniper wood from Gordion suggested a possible regional difference in calibration curves. If true, this could push the eruption date back to the 17th century BC. Others argue that IntCal20 already accounts for such variations.
The IntCal20 curve does not rule out a 17th-century BC eruption but suggests the eruption likely happened mostly in the 16th century BC. This helps reduce the long-standing conflict between radiocarbon and archaeological dates. However, the exact year of the eruption is still unknown.
A major eruption like the Minoan one would leave clues in environmental records, such as ice cores and tree rings. Studies of Minoan magma suggest the eruption released between 0.3 and 35.9 trillion grams of sulfur. The higher end of this range could cause major climate changes detectable in ice cores and tree rings. Tree rings allow precise dating to the exact year and can reveal climate details with high accuracy.
In 1987, a large sulfate spike in Greenland ice cores around 1644 ± 20 BC was linked to the Minoan eruption based on early radiocarbon dates. In 1988, a major climate disruption and frost rings in 1627 ± 0 BC were also linked to the eruption. However, archaeologists who supported a late 16th-century BC date were not convinced because no direct connection between these events and the eruption was found.
Since 2003, studies of volcanic ash in the 1644 ± 20 BC sulfate layer failed to match it to Santorini. Instead, the ash was linked to Mount Aniakchak’s eruption, ruling out the Minoan eruption as the cause. In 2019, a revised Greenland ice core timeline was proposed based on matching frost ring data and sulfate levels.
Historical impact
The eruption destroyed the settlement at Akrotiri on Santorini, which was covered by a thick layer of pumice and ash. Evidence from the site shows that some survivors returned later to try to retrieve their belongings and possibly to bury those who had died.
The eruption was felt at Minoan sites on Crete. In northeastern Crete, earthquakes damaged areas like Petras, while tsunamis up to 9 meters high hit coastal places such as Palaikastro. Ash and pumice fell across the island, and in some areas, people collected and stored the material.
After the eruption, the Minoans recovered quickly, and the time that followed is seen as the most successful period of Minoan culture. Many damaged sites, including Petras and Palaikastro, were rebuilt. At Palaikastro, new buildings were made using strong stone masonry. New palaces were also built at Zakros and Phaistos. However, other places, such as Galatas and Kommos, declined over time.
The long-term effects of the eruption are still debated. In the immediate aftermath, some puzzling changes occurred, such as the filling of lustral basins. In their book The Troubled Island, Driessen and MacDonald argued that the wealth of materials found after the eruption hid serious economic and political problems that eventually led to the collapse of Neopalatial society. Later evidence suggests this was not a widespread pattern across the island.
Some researchers believe a volcanic winter caused by the eruption around 1600 BC may be linked to records in ancient Chinese texts about the fall of the Xia dynasty. The Bamboo Annals describe the collapse of the Xia and the rise of the Shang dynasty around 1618 BC, mentioning events like "yellow fog, a dim sun, three suns, frost in July, famine, and the withering of crops."
Apocalyptic rainstorms that severely damaged parts of Egypt were recorded on the Tempest Stele of Ahmose I. These storms may have been caused by short-term climate changes from the Theran eruption. The dates of Ahmose I’s reign are debated by Egyptologists, with estimates ranging from 1570–1546 BC to 1539–1514 BC. A carbon dating of his mummy suggests a date of 1557 BC. However, this date does not fully align with estimates for the Theran eruption. In 2025, carbon dating of materials from the 18th Dynasty, such as mudbricks from Ahmose I’s temples, showed dates that did not match the eruption of Thera.
If the eruption occurred during Egypt’s Second Intermediate Period, the lack of Egyptian records about it might be due to the chaos in Egypt at that time.
Some believe the damage from the storms was caused by an earthquake following the Thera eruption. Others suggest the damage resulted from a war with the Hyksos, with the storm reference symbolizing the chaos the Pharaoh aimed to control. Other Egyptian texts, like the Speos Artemidos stele, describe storms that are clearly symbolic, such as Hatshepsut’s victory over chaos and darkness.
The eruption of Thera and its volcanic effects may have inspired the myth of the Titanomachy in Hesiod’s Theogony. The story might have included elements from western Anatolian folklore, especially from the eastern Aegean region. As the myth spread to mainland Greece, it may have absorbed influences from the east.
Hesiod’s descriptions have been compared to volcanic activity. For example, Zeus’s thunderbolts are likened to volcanic lightning, the boiling earth and sea to magma chamber breaches, and immense heat to phreatic explosions.
Spyridon Marinatos, who discovered the Akrotiri site, suggested the Minoan eruption is reflected in Plato’s story of Atlantis. This idea is still popular in media, such as the BBC’s Atlantis series. However, scholars do not support this view.
Geologist Barbara J. Sivertsen proposes a connection between the Santorini eruption (around 1600 BC) and the Exodus of the Israelites from Egypt as described in the Bible.